Optical fingerprint sensor module and package thereof

ABSTRACT

The present invention provides an optical fingerprint sensor module and its package thereof, which comprises a carrier, at least one light emitting diode, at least one image sensor and a molding compound. When a user&#39;s fingerprint is generated for recognition, the light emitting diode provides enough light sources for lighting and helping the image sensor to capture and sense an image of the fingerprint. A top emitting surface of the light emitting diode is higher than a top of the image sensor, such that interferences from the side light of the light emitting diode with the image sensor can be effectively avoided. Besides, the molding compound comprises a caved portion corresponding to the image sensor on a vertical plane. By designing above, it successfully achieves the purpose of reducing a thickness of the optical fingerprint sensor package.

REFERENCE TO RELATED APPLICATION

This patent application is based on U.S. Provisional Patent Application Ser. No. 62/425,715, filed 23 Nov. 2016.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an optical package structure, and more particularly to an optical fingerprint sensor module and its package thereof.

Description of the Prior Art

Fingerprint recognition has been widely utilized in a variety of technical fields, especially in those fields when security verifications are needy. For example, portable communication devices (i.e. mobile phone, a tablet PC), financial transactions, home-based security and so on, all demand sophisticated fingerprint recognition apparatuses, and therefore making the fingerprint recognition apparatus an unique and standard manner of a person's distinctive identity verification.

When speaking of mechanisms of fingerprint recognition technology, as far as we know, there are mainly two types of fingerprint recognition apparatuses used in recent technology, such as a semiconductor type and an optical type according to their different mechanism. However, since the structure of the semiconductor type is usually much more complicated and requires high complexity when being manufactured, the optical type is advantageous and profitable instead. In general, an optical type fingerprint recognition is characterized by its optical imaging and optical sensing technique, in which at least one light source and an image sensor are certainly necessary. Generally speaking, portable electronic devices nowadays, for example: smart phones, are usually equipped with at least one proximity optical sensing module in order to achieve the objectives of fingerprint recognition. In other words, when the above-mentioned electronic device (i.e. smart phones) receives an input, for example a user's fingerprint, then the portable electronic device senses the fingerprint and determines if it is valid. To be more specific, how the portable electronic device works is related to a light emitting diode (LED) which is utilized to emit a light source. Then, the light source provides enough lighting for helping the image sensor to acquire an image of the user's fingerprint. As such, a comparison module in rear end is able to perform analysis and validation accordingly to determine if the fingerprint is certificated. However, it should be noticed that problems arise when the at least one light source are usually designed to surround the image sensor on a horizontal plane. And because of that, the side light of the at least one light source will produce various interferences with the image sensor, thereby affecting the accuracy and precision of the sensing and recognition results.

Besides, since the optical fingerprint apparatus is usually composed of an optical QFN (Quad-Flat-No-Lead) package therein, thickness of the optical package is also very critical. Various prior arts have made a lot of efforts on reducing the thickness for not only enhancing the accuracy and precision of the sensing result but also lowering its fabricating cost. Nevertheless, it is believed that so far those achievements are still limited and cannot be utilized extensively. Therefore, on account of above, to overcome the abovementioned problem, it should be obvious that there is indeed an urgent need for the professionals in the field for a new optical fingerprint sensor package to be developed that can effectively solve those above mentioned problem occurring in the prior design.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned disadvantages, one major objective in accordance with the present invention is provided for a novel optical fingerprint sensor module and its package thereof. By employing the optical fingerprint sensor module and its package of the present invention, it can be utilized so as to increase the accuracy and precision of the sensing and recognition results.

For achieving the above mentioned objectives, the present invention provides an optical fingerprint sensor module, which comprises a carrier, at least one light emitting diode, and at least one image sensor. The at least one light emitted diode is disposed on the carrier for providing at least one light source. The at least one image sensor is disposed on the carrier and being electrically connected with the carrier. Moreover, a top emitting surface of the at least one light emitted diode is higher than a top of the at least one image sensor. As such, when a user's fingerprint is generated for recognition, the at least one light source is provided for lighting and helping the at least one image sensor to capture and sense an image of said fingerprint, and interferences from the side light of the at least one light emitting diode with the image sensor can be effectively avoided.

In one embodiment of the present invention, the carrier can be a substrate. In other embodiment of the present invention, the carrier alternatively can be a lead frame as well.

Furthermore, according to one embodiment of the present invention, the carrier may further comprise at least one protruding part, and the at least one light emitting diode is disposed on the at least one protruding part. Therefore, the top emitting surface of the light emitted diode is higher than the top of the at least one image sensor, and interferences from the side light of the light emitting diode with the image sensor will be successfully depressed.

According to another embodiment of the present invention, the at least one light emitting diode may further be disposed on at least one lead frame, and the at least one lead frame is disposed on the carrier. By employing this design, the top emitting surface of the light emitted diode can also be higher than the top of the at least one image sensor, and interferences from the side light of the light emitting diode with the image sensor will be successfully depressed as well.

In one embodiment, the at least one image sensor is connected with the carrier through a plurality of pads, and the at least one light emitting diode is connected with the carrier or the lead frame through at least one electrical bump. The light emitting diode is flip-chip mounted upon the carrier or the lead frame through the at least one electrical bump.

In another aspect of the present invention, an optical fingerprint sensor package thereof is provided. The optical fingerprint sensor package comprises a carrier, at least one light emitting diode, at least one image sensor, and a molding compound. The at least one light emitted diode is disposed on the carrier for providing at least one light source. The at least one image sensor is disposed on the carrier and being electrically connected with the carrier. A top emitting surface of the at least one light emitted diode is higher than a top of the at least one image sensor by disposing the at least one light emitting diode on either a protruding part of the carrier or on an additional lead frame. The molding compound covers the carrier, the at least one light emitting diode and the at least one image sensor, and the molding compound comprises a caved portion which is corresponding to the image sensor on a vertical plane. By such design rules, a thickness of a first structure composed of the carrier, the at least one image sensor and the molding compound is thinner than that of a second structure composed of the carrier, the at least one light emitting diode and the molding compound. As a result, a thickness of the optical fingerprint sensor package thereof the present invention is tremendously decreased, and the fabricating cost thereof can be reduced accordingly, meanwhile, enhancing the accuracy and precision of the sensing result of the present invention.

In one embodiment of the present invention, the molding compound is made of light transparent material. In one embodiment of the present invention, the carrier is a substrate or alternatively is a lead frame.

These and other objectives of the present invention will become obvious to those of ordinary skill in the art after reading the following detailed description of preferred embodiments.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:

FIG. 1 shows a cross sectional view of an optical fingerprint sensor module in accordance with a first embodiment of the present invention.

FIG. 2 shows a cross sectional view of an optical fingerprint sensor package in accordance with a second embodiment of the present invention.

FIG. 3 shows a detailed cross sectional view of an optical fingerprint sensor package according to FIG. 2.

FIG. 4 shows a cross sectional view of an optical fingerprint sensor module in accordance with a third embodiment of the present invention.

FIG. 5 shows a cross sectional view of an optical fingerprint sensor package in accordance with a fourth embodiment of the present invention.

FIG. 6 shows a detailed cross sectional view of an optical fingerprint sensor package according to FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

The embodiments described below are illustrated to demonstrate the technical contents and characteristics of the present invention and to enable the persons skilled in the art to understand, make, and use the present invention. However, it shall be noticed that, it is not intended to limit the scope of the present invention. Therefore, any equivalent modification or variation according to the spirit of the present invention is to be also included within the scope of the present invention.

The present invention discloses an optical fingerprint sensor module which can be utilized for eliminating interferences from the side light of light sources and meanwhile increasing both the light sensing and recognition efficiency. Please refer to FIG. 1 first, which shows a cross sectional view of an optical fingerprint sensor module in accordance with a first embodiment of the present invention. As shown in FIG. 1, the optical fingerprint sensor module 1 of the present invention comprises at least: a carrier 10, at least one light emitting diode 20, and at least one image sensor 30. The light emitted diode 20 is disposed on the carrier 10 for providing at least one light source. The image sensor 30 is disposed on the carrier 10 and being electrically connected with the carrier 10. In one embodiment of the present invention, the carrier 10 can be a substrate or a lead frame. The image sensor 30 is connected with the carrier 10 through pad 33, and the light emitting diode 20 is connected with the carrier 10 through at least one electrical bump 24. In other words, the light emitting diode 20 is flip-chip mounted upon the carrier 10 through the at least one electrical bump 24.

According to the embodiment of the present invention, how the image sensor 30 of the present invention is mounted upon the carrier 10 is not limited, and should comprise both designs of Ball Grid Array (BGA) and Land Grid Array (LGA). Practically, when a user's fingerprint is generated for recognition, for example, in portable communication devices (i.e. mobile phone, a tablet PC), financial transactions, or home-based security, the light emitting diode 20 gives enough light source for lighting and helping the image sensor 30 to capture and sense an image of the fingerprint. Since the side light of the light emitting diode 20 will generate unexpected interferences with the image sensor 30, thus affecting its sensing accuracy, one major objective of the present invention is to eliminate these interferences from the side light of the light emitting diode 20. What the present invention proposes is to “raise” the position of the light emitting diode 20, for example, using a protruding part 12 of the carrier 10 or alternatively comprising an additional lead frame (which will be discussed in the following embodiment of the present invention later).

Thus, as shown in FIG. 1, the light emitting diode 20 is disposed on the protruding part 12 of the carrier 10, and the top emitting surface of the light emitted diode 20 will be controlled to be higher than a top of the image sensor 30. Therefore, the side light of the light emitting diode 20 will not be able to interact with the image sensor 30. By employing this manner of design, it is apparent that interferences from the side light of the light emitting diode 20 with the image sensor 30 can be effectively avoided.

Please refer to FIG. 2, which shows a cross sectional view of an optical fingerprint sensor package in accordance with a second embodiment of the present invention. As shown in FIG. 2, the optical fingerprint sensor package 2 of the present invention comprises at least: a carrier 10, at least one light emitting diode 20, at least one image sensor 30, and furthermore a molding compound 40. The light emitted diode 20 is disposed on the carrier 10 for providing at least one light source. The image sensor 30 is disposed on the carrier 10 and being electrically connected with the carrier 10. The image sensor 30 is connected with the carrier 10 through pad 33, and the light emitting diode 20 is connected with the carrier 10 through at least one electrical bump 24. In general, the light emitting diode 20 is flip-chip mounted upon the carrier 10 through the at least one electrical bump 24. According to the embodiment of the present invention, how the image sensor 30 of the present invention is mounted upon the carrier 10 is not limited, and should comprise both designs of Ball Grid Array (BGA) and Land Grid Array (LGA).

Practically, when a user's fingerprint is generated for recognition, for example, in portable communication devices (i.e. mobile phone, a tablet PC), financial transactions, or home-based security, the light emitting diode 20 gives enough light source for lighting and helping the image sensor 30 to capture and sense an image of the fingerprint. Since the light emitting diode 20 is disposed on the protruding part 12 of the carrier 10 and the top emitting surface of the light emitted diode 20 is higher than a top of the image sensor 30, interferences from the side light of the light emitting diode 20 with the image sensor 30 are prevented. Moreover, the molding compound 40 is configured to cover the carrier 10, the light emitting diode 20 and the image sensor 30, and the molding compound 40 comprises a caved portion 44 which is corresponding to the image sensor 30 on a vertical plane. Please refer to FIG. 3, it is shown that a first structure 100 is composed of the carrier 10, the image sensor 30 and the molding compound 40, and a second structure 200 is composed of the carrier 10, the light emitting diode 20 and the molding compound 40. Since the caved portion 44 of the molding compound 40 is formed upon the image sensor 30 on a vertical plane, a thickness D1 of the first structure 100 is controlled to be thinner than a thickness D2 of the second structure 200. Therefore, the optical fingerprint sensor package 2 of the present invention achieves the thinnest optical fingerprint package and being much more competitive for not only lowering its manufacturing and fabrication cost, but also enhancing its sensing accuracy and precision.

In one embodiment of the present invention, the molding compound 40 is made of light transparent material. And, the optical fingerprint sensor package 2 of the present invention employs the QFN (Quad-Flat-No-Lead) process design, nevertheless, the present invention is certainly not limited thereto.

Next, please refer to FIG. 4, which shows a cross sectional view of an optical fingerprint sensor module in accordance with another embodiment of the present invention. As shown in FIG. 4, the optical fingerprint sensor module 1′ of the present invention comprises at least: a carrier 10′, at least one light emitting diode 20′, and at least one image sensor 30′. The light emitted diode 20′ is disposed on the carrier 10′ for providing at least one light source. The image sensor 30′ is disposed on the carrier 10′ and being electrically connected with the carrier 10′. In such embodiment of the present invention, the carrier 10′ can be a substrate or a lead frame, and the image sensor 30′ is connected with the carrier 10′ through pad 33′. According to the embodiment of the present invention, similarly, how the image sensor 30′ of the present invention is mounted upon the carrier 10′ is not limited, and should comprise both designs of Ball Grid Array (BGA) and Land Grid Array (LGA).

As such, when a user's fingerprint is generated for recognition, for example, in portable communication devices (i.e. mobile phone, a tablet PC), financial transactions, or home-based security, the light emitting diode 20′ gives enough light source for lighting and helping the image sensor 30′ to capture and sense an image of the fingerprint. Since the side light of the light emitting diode 20′ may generate unexpected interferences with the image sensor 30′, thus affecting its sensing accuracy, one major objective of the present invention is to eliminate these interferences from the side light of the light emitting diode 20′. In order to “raise” the position of the light emitting diode 20′, what we propose in this embodiment is to comprise at least one additional lead frame 60.

As shown in FIG. 4, it is clear that the lead frame 60 is disposed on the carrier 10′, and the light emitting diode 20′ is disposed on the lead frame 60 through at least one electrical bump 24′. According to the embodiment of the present invention, the light emitting diode 20′ is flip-chip mounted upon the carrier 10′ through the at least one electrical bump 24′ and the lead frame 60. By such arrangements, the top emitting surface of the light emitted diode 20′ will also be controlled to be higher than a top of the image sensor 30′. Therefore, the side light of the light emitting diode 20′ will not be able to interfere with the image sensor 30′. And by employing this manner of design, it is apparent that interferences from the side light of the light emitting diode 20′ with the image sensor 30′ is effectively suppressed.

FIG. 5 shows a cross sectional view of an optical fingerprint sensor package in accordance with another embodiment of the present invention. As shown in FIG. 5, the optical fingerprint sensor package 2′ of the present invention comprises at least: a carrier 10′, at least one light emitting diode 20′, at least one image sensor 30′, and furthermore a molding compound 40′. The light emitted diode 20′ is disposed on the carrier 10′ for providing at least one light source. The image sensor 30′ is disposed on the carrier 10′ and being electrically connected with the carrier 10′. The image sensor 30′ is connected with the carrier 10′ through pad 33′, and the light emitting diode 20′ is connected with the carrier 10′ through at least one electrical bump 24′ and at least one lead frame 60. In one embodiment, the light emitting diode 20′ is flip-chip mounted upon the carrier 10′ through the at least one electrical bump 24′ and the lead frame 60. According to the embodiment of the present invention, how the image sensor 30′ of the present invention is mounted upon the carrier 10′ is not limited, and should comprise both designs of Ball Grid Array (BGA) and Land Grid Array (LGA).

Practically, when a user's fingerprint is generated for recognition, for example, in portable communication devices (i.e. mobile phone, a tablet PC), financial transactions, or home-based security, the light emitting diode 20′ gives enough light source for lighting and helping the image sensor 30′ to capture and sense an image of the fingerprint. Since the light emitting diode 20′ is disposed on the carrier 10′ through an additional dead frame 60, the top emitting surface of the light emitted diode 20′ is higher than a top of the image sensor 30′, and therefore interferences from the side light of the light emitting diode 20′ with the image sensor 30′ are prevented.

Moreover, in this embodiment, the molding compound 40′ is configured to cover the carrier 10′, the light emitting diode 20,′ the lead frame 60 and the image sensor 30′, and the molding compound 40′ comprises a caved portion 44′ which is corresponding to the image sensor 30′ on a vertical plane. Please refer to FIG. 6, it is shown that a first structure 100′ is composed of the carrier 10′, the image sensor 30′ and the molding compound 40′, and a second structure 200′ is composed of the carrier 10′, the light emitting diode 20′, the lead frame 60 and the molding compound 40′. Since the caved portion 44′ of the molding compound 40′ is formed upon the image sensor 30′ on a vertical plane, it can be seen that a thickness D3 of the first structure 100′ is controlled to be thinner than a thickness D4 of the second structure 200′. Therefore, the optical fingerprint sensor package 2′ of the present invention achieves the thinnest optical fingerprint package and being much more competitive for not only lowering its manufacturing and fabrication cost, but also enhancing its sensing accuracy and precision.

According to the embodiment of the present invention, the molding compound 40′ is made of light transparent material. And, the optical fingerprint sensor package 2′ of the present invention employs the QFN (Quad-Flat-No-Lead) process design, nevertheless, the present invention should be certainly not limited thereto as well.

Therefore, to sum up, the present invention indeed provides a novel and inventive optical fingerprint sensor module and package thereof which have never been seen or proposed ever before. The proposed invention employs an additional lead frame or a protruding part of the carrier so as to raise the position of the light emitting diode. As such, the top emitting surface of the light emitting diode can be successfully maintained to be higher than the top of the image sensor. And interferences from the side light of the light source with the image sensor are accordingly prevented, thereby enhancing sensing accuracy and precision of the optical fingerprint sensor module.

Furthermore, as compared to the prior design, the present invention proposed an optical fingerprint sensor package, comprising a caved portion of the molding compound which is corresponding to the image sensor on a vertical plane. As a result, the proposed optical fingerprint sensor package is advantageous of not only thin thickness and low fabrication cost, but also less complexity and area consuming. Thus, it is believed that the present invention is instinct, effective and highly competitive for incoming technology, industries and researches developed in the future and shall be patentable as well.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the invention and its equivalent. 

What is claimed is:
 1. An optical fingerprint sensor module, comprising: a carrier; at least one light emitted diode, which is disposed on said carrier for providing at least one light source; and at least one image sensor disposed on said carrier and being electrically connected with said carrier, wherein when a user's fingerprint is generated for recognition, said at least one light source is provided for lighting and helping said image sensor to capture and sense an image of said fingerprint, and a top emitting surface of said light emitted diode is higher than a top of said at least one image sensor.
 2. The optical fingerprint sensor module of claim 1, further comprising at least one lead frame, wherein said at least one lead frame is disposed on said carrier, and said at least one light emitting diode is disposed on said at least one lead frame, such that said top emitting surface of said light emitted diode is higher than said top of said at least one image sensor.
 3. The optical fingerprint sensor module of claim 2, further comprising a plurality of pads, which are in connection with said carrier and said at least one image sensor.
 4. The optical fingerprint sensor module of claim 3, further comprising at least one electrical bump, which is in connection with said lead frame and said at least one light emitting diode.
 5. The optical fingerprint sensor module of claim 4, wherein said at least one light emitting diode is flip-chip mounted upon said carrier through said at least one electrical bump and said at least one lead frame.
 6. The optical fingerprint sensor module of claim 1, wherein said carrier further comprises at least one protruding part, and said at least one light emitting diode is disposed on said at least one protruding part such that said top emitting surface of said light emitted diode is higher than said top of said at least one image sensor.
 7. The optical fingerprint sensor module of claim 6, further comprising a plurality of pads, which are in connection with said carrier and said at least one image sensor.
 8. The optical fingerprint sensor module of claim 7, further comprising at least one electrical bump, which is in connection with said protruding part of said carrier and said at least one light emitting diode.
 9. The optical fingerprint sensor module of claim 8, wherein said at least one light emitting diode is flip-chip mounted upon said carrier through said at least one electrical bump and said protruding part.
 10. The optical fingerprint sensor module of claim 1, wherein said carrier is a substrate or a lead frame.
 11. The optical fingerprint sensor module of claim 1, further comprising a molding compound, covering said carrier, said light emitting diode and said image sensor, wherein said molding compound comprises a caved portion which is corresponding to said image sensor such that a thickness of a first structure composed of said carrier, said image sensor and said molding compound is thinner than that of a second structure composed of said carrier, said light emitting diode and said molding compound.
 12. The optical fingerprint sensor module of claim 11, wherein said molding compound is made of light transparent material.
 13. An optical fingerprint sensor package, comprising: a carrier; at least one light emitted diode, which is disposed on said carrier for providing at least one light source; at least one image sensor disposed on said carrier and being electrically connected with said carrier, wherein when a user's fingerprint is generated for recognition, said at least one light source is provided for lighting and helping said image sensor to capture and sense an image of said fingerprint, and a top emitting surface of said light emitted diode is higher than a top of said at least one image sensor; and a molding compound, covering said carrier, said at least one light emitting diode and said at least one image sensor, wherein said molding compound comprises a caved portion which is corresponding to said at least one image sensor such that a thickness of a first structure composed of said carrier, said at least one mage sensor and said molding compound is thinner than that of a second structure composed of said carrier, said at least one light emitting diode and said molding compound.
 14. The optical fingerprint sensor package of claim 13, wherein said molding compound is made of light transparent material.
 15. The optical fingerprint sensor package of claim 13, further comprising at least one lead frame, wherein said at least one lead frame is disposed on said carrier, and said at least one light emitting diode is disposed on said at least one lead frame, such that said top emitting surface of said light emitted diode is higher than said top of said at least one image sensor.
 16. The optical fingerprint sensor package of claim 15, further comprising at least one electrical bump, which is in connection with said lead frame and said at least one light emitting diode.
 17. The optical fingerprint sensor package of claim 16, wherein said at least one light emitting diode is flip-chip mounted upon said carrier through said at least one electrical bump and said at least one lead frame.
 18. The optical fingerprint sensor package of claim 13, wherein said carrier further comprises at least one protruding part, and said at least one light emitting diode is disposed on said at least one protruding part such that said top emitting surface of said light emitted diode is higher than said top of said at least one image sensor.
 19. The optical fingerprint sensor package of claim 18, further comprising at least one electrical bump, which is in connection with said protruding part of said carrier and said at least one light emitting diode.
 20. The optical fingerprint sensor package of claim 19, wherein said at least one light emitting diode is flip-chip mounted upon said carrier through said at least one electrical bump and said protruding part.
 21. The optical fingerprint sensor package of claim 13, wherein said carrier is a substrate or a lead frame. 